Kendra Wilkinson
The former Playboy Bunny was once Hugh Hefner's girlfriendGetty

Kendra Wilkinson has described sleeping with Hugh Hefner as a "job", admitting she needed be drunk or stoned to survive her nights with the Playboy boss.

The 29-year-old reality star, who is competing in the latest series of I'm a Celebrity, famously started living with the then 78-year-old mogul when she was just 18.

Their unusual relationship came to end in 2008 when she got engaged to former NFL player Hank Baskett following a whirlwind romance.

Opening up about their sex life in her 2010 memoir, Sliding into Home, the mother-of-two said her love-making sessions with Hefner would last 60 seconds and she never got any pleasure from it.

"I was usually very drunk doing those evenings; I tended not to care about much until the next day. I had to be very drunk or smoke lots of weed to survive those nights," she said.

"At about the minute mark, I pulled away and it was done. It was like a job. Clock in, clock out. It's not like I enjoyed having sex with him."

Wilkinson was less forthcoming during her heart-to-heart talk with TV presenter and model Melanie Sykes in the jungle earlier this week. Although she revealed how she became Hefner's girlfriend, she didn't dish the intimate details.

"I was living in the smallest apartment with the ugliest **** and I was praying for anything to get me out of there," she explained.

"I didn't know that sex was involved because I knew nothing about Playboy. I just graduated high school. [But then] he's like, 'Do you wanna come upstairs?' [and I said] 'Sure, let's have fun.'"

When asked if she was obligated to have sex with Hefner, Wilkinson replied: "You're not obligated it's your choice."

"I moved in and weeks went by and I didn't know that sex was involved," she added. "Because I knew nothing about Playboy. I had just graduated high school."

Hefner has since moved on with Crystal Harris, who he married in 2012.